Section for the manufacture of hollow body elements, hollow body element and component assembly

ABSTRACT

A section ( 10; 110 ) is provided for the manufacture of hollow body elements, in particular for the manufacture of pierce and rivet nuts having a square or rectangular outline in plan view and a ring-like piercing section ( 36; 236 ) at a side confronting a component consisting of a sheet metal material or the like. The section ( 10; 210 ) is at least substantially rectangular in cross-section with two bars ( 14, 16; 214, 216 ) at the side ( 12; 212 ) later confronting the component. The bars are spaced apart and extend parallel to the longitudinal sides ( 18, 20; 218, 220 ) of the section, are likewise at least substantially rectangular in cross-section and form, in the finished element ( 11, 211 ), a feature providing security against rotation. The bars respectively each have an inclined flank ( 68, 70; 268, 270 ) at the inner side which forms an undercut ( 69, 71; 269, 271 ). The specification also describes and claims hollow body elements made from such a section and component assemblies formed by attaching such hollow body elements to sheet metal parts.

FIELD OF THE INVENTION

The present invention relates to a section for the manufacture of hollowbody elements, in particular for the manufacture of pierce and rivetnuts having a square or rectangular outline in plan view which are to beprovided in a later process with a ring-like piercing section at a sideconfronting a component consisting of a sheet metal material or thelike. Furthermore, the invention relates to hollow body elements whichare manufactured from portions of the section and also to componentassemblies which result from attachment of the hollow body elements tocomponents.

BACKGROUND OF THE INVENTION

Methods for the manufacture of hollow body elements, such as nutelements, for the attachment to components normally consisting of sheetmetal are known. In such known methods the hollow body elements areprovided with an at least substantially square or rectangular outline bycutting off individual lengths of the section, which is present in theform of a bar section or of a coil after the previous punching ofrespective apertures in the section, optionally with the subsequentformation of a thread cylinder.

A method of the initially named kind and also the corresponding hollowbody elements are for example known from U.S. Pat. No. 4,971,499. Hollowbody elements are also sold by the Company Profil VerbindungstechnikGmbH & Co. KG in Germany under the designation HI rectangular nuts.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a section from whichhollow body elements, in particular rectangular nut elements can beproduced with favourably priced manufacture, with the hollow bodyelements having improved mechanical characteristics in comparison toknown elements and after attachment to a component of sheet metal, forexample a higher pull-out resistance and an improved security againstrotation. Moreover, such hollow body elements should show a reducednotching action so that the fatigue characteristics of componentassemblies comprising a component normally consisting of sheet metal andhollow body elements attached to the latter are also improved underdynamic loads.

In order to satisfy this object a section of the initially named kind isprovided which is characterised in that, the section is at leastsubstantially rectangular in cross-section with two bars at the sidelater confronting the component which are spaced apart and extendparallel to the longitudinal sides of the section, are likewise at leastsubstantially rectangular in cross-section and form, in the finishedelement a feature providing security against rotation and in that thebars respectively have an inclined flank at the inner side which formsan undercut.

The ring-like piercing section which lies at the centre of the elementcan be circular, oval or polygonal. In all these forms the notch actionis significantly reduced relative to a rectangular piercing section asin the prior art. Through the undercuts in the region of the bars anexcellent press-out resistance and a high security against rotation areachieved.

The manufacture from a section, which is present either in the form of abar section or in the form of a coil in which the section already hasthe basic shape of the element, makes it possible to dispense withcomparatively costly cold heading machines and permits instead of thisthe manufacture of the elements in a normal punching press which isequipped with progressive tooling for carrying out the individualmanufacturing steps. The manufacture in a punching press utilizingprogressive tooling is particularly cost favourable in comparison to theuse of cold heading machines. Manufacture on a transfer press is alsopossible under the same conditions. In this arrangement the separatingprocess must be displaced into the first stage.

Particularly favourable sections for manufacturing hollow body elementsresult from the sections which are able to be manufactured by coldrolling, for example from a 35B2 steel material. The particular sectionsof the invention lead, on the one hand, to elements which are favourableweight-wise and, on the other hand, also to elements which can bemanufactured at favourable cost and to elements which have excellentmechanical characteristics.

With a hollow body element for the attachment to a component, inparticular to a component consisting of sheet metal, in which the hollowbody element has bars at two opposite sides extending parallel to oneanother which form a security against rotation with the component and acentrally arranged punched aperture extending perpendicular to thecomponent side, the punched aperture optionally having a threadcylinder, the invention provides that a ring-like projection is presentat the side of the hollow body element that faces the component andconcentric to the punched aperture, the ring-like projection beingformed as a piercing section and that a recessed region is presentbetween the bars and the ring-like piercing section, with bars onlybeing present at two opposite sides of the hollow body element andhaving an inclined flank at the side facing the ring-like piercingsection which forms an undercut.

Since a ring-like piercing section is present a ring-like slug ispunched out of the component during the attachment of the hollow bodyelement so that a notch effect in the region of the circular apertureproduced in the component need no longer be feared. That is to say therectangular edges present in the known elements, which arose as resultof the previous rectangular piercing section are, so to say, omitted. Inthis connection it is noted that in the prior art the rectangularpiercing section is defined by the cross-section of the section that isused, whereas in the present invention one makes use of the specialpiercing section which is produced in accordance with the invention byan upsetting process.

Particularly favourable variants of the hollow body element result fromthe claims 6 to 14.

Further advantages of the section of the invention, of the hollow bodyelement of the invention and of the component assemblies in accordancewith the invention are to be found in the following description ofpreferred examples which are explained further with reference to thedrawings. In the drawings are shown:

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 a perspective representation of a section of a first section inaccordance with the invention for the manufacture of hollow bodyelements,

FIGS. 2A-F a series of drawings which show the individual method stepswhich are required in order to manufacture a hollow body element inaccordance with the invention from the section of FIG. 1,

FIG. 3 a partly sectioned drawing to explain the carrying out of theupsetting process in accordance with FIG. 2B in a station of progressivetooling in a punching press,

FIGS. 4A-F a series of drawings to set forth the precise shape of thehollow body element in accordance with the invention manufactured fromthe section of FIG. 1,

FIG. 5 a partly sectioned representation of a component assemblycomprising a sheet metal part and a hollow body element in accordancewith the invention attached thereto, the hollow body element being inaccordance with FIG. 4,

FIGS. 6A-C drawings to explain the design of a die in accordance withthe invention for the attachment of the element of FIG. 4 to a sheetmetal part,

FIG. 7 a drawing for the representation of the attachment of a furthercomponent to the component assembly of FIG. 5,

FIG. 8 a perspective representation of a section of a second section ofthe invention for the manufacture of hollow body elements,

FIGS. 9A-E a series of drawings to set forth the precise form of thehollow body elements in accordance with the invention manufactured fromthe section of FIG. 8,

FIG. 10 a partly sectioned illustration of a component assemblycomprising a sheet metal part and a hollow body element in accordancewith the invention attached thereto, the hollow body element being inaccordance with FIGS. 9A to E,

FIG. 11 a drawing to represent the attachment of a further component tothe component assembly of FIG. 10,

FIGS. 12A+B drawings to explain the design of a die in accordance withthe invention for the attachment of the elements in accordance with theFIGS. 9A to 9E to a sheet metal part,

FIG. 13 a perspective illustration of an earlier proposed section forthe manufacture of hollow body elements,

FIGS. 14A-E a series of drawings to set forth the precise form of thehollow body element in accordance with the invention manufactured fromthe section of FIG. 13,

FIG. 15 a partly sectioned representation of a component assemblycomprising a sheet metal part and a hollow body element in accordancewith FIGS. 14A to 14E attached thereto,

FIG. 16 a drawing for the representation of the attachment of a furthercomponent to the component assembly of FIG. 15, and

FIGS. 17A-C drawings to explain the design of a die for the attachmentof the element in accordance with the FIGS. 14A to 14E to a sheet metalpart.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1 shows a perspective representation of a first section 10 inaccordance with the invention which can be used for the manufacture ofhollow body elements 11 (FIG. 4) in accordance with the invention. Thesection 10 is present either in the form of a bar of for example 6meters length or is delivered by the material manufacturer in the formof a coil. It is a cold rolled section. Preferred materials are allsteel types in accordance with DIN 1654, but also NE-metals such asaluminium or the like.

The section is at least substantially rectangular in cross-section andhas additionally two bars 14, 16 having a spacing A from one another atthe side 12 which later faces the component. The bars extend parallel tothe longitudinal sides 18 and 20 of the section 10 and are approximatelytrapezoidal in cross-section. However, they only have one inclined innerside or flank 68, 70. One can also consider the shape of the section insuch a way that it is at least substantially rectangular with a broad,but not very deep groove 22 of trapezoidal cross-section at the side 12facing the component, with the groove 22 likewise extending parallel tothe longitudinal sides 18, 20 of the section.

The reference numeral 21 points to the central longitudinal axis of thesection the “end face” 23 of which represents any desired plane of thesection standing perpendicular to the central longitudinal axis 21(since the section continues on the left-hand side of the plane 23). Theaxis 24 likewise stands perpendicular to the central longitudinal axis21 of the section and forms, as will be explained later, the centralaxis of the ring-like piercing section which has yet to be formed for ahollow body element later manufactured from the section.

As indicated in the drawing of FIG. 1 the inclined flank 70 forms anangle α in the plane 23 with this axis 24. The same applies for theflank 68 (although the angle α is not drawn in there). The angle αpreferably lies in the range between 3° and 45°, in particular between7° and 30°.

In this example an element 11 in accordance with the FIGS. 4A-F ismanufactured from the section in accordance with the invention of FIG.1. The general shape of the element, which is straightforwardly evidentfrom FIG. 4 will first be described in more detail later. First of allthe manufacturing method will be explained in more detail with referenceto the FIGS. 2A-2F and with reference to FIG. 3. FIGS. 2A-F all show across-section (partly only a half section) through the section 10 ofFIG. 1 perpendicular to its longitudinal extent L, with the axis 24 inFIG. 2 corresponding to the axis 24 of FIG. 1 and being arrangedperpendicular to the longitudinal extent L of the section 10. Thecross-sectional plane also stands perpendicular to the longitudinaldirection L.

The section 10 runs in the longitudinal direction L in a punching press38 equipped with progressive tooling 26 (FIG. 3) with the progressivetooling having five stations for carrying out the steps shown in FIGS.2A-E. The first station is shown in cross-section in FIG. 3 and servesfor the upsetting process in accordance with FIG. 2B. In this processpressure is exerted on the upper side 30 of the section 10 by means awayplunger 28 which comes from above in FIG. 3 and FIG. 2B and a materialflow is generated locally in the section 10 in the region of the axis 24by means of a die 32 (FIG. 3) arranged beneath the bar section 10, sothat a cylindrical recess 34 is produced in the topside 30 of the barsection 10 and a cylindrical projection 36 is produced at the componentside 12 of the bar section 10. The volume of the cylindrical recess 34corresponds to the volume 36 of the cylindrical projection.

As already mentioned, FIG. 3 shows a partly sectioned representation ofa first station of progressive tooling 26 which is arranged in apunching press 38, with only a part of the punching press and a part ofthe progressive tooling being shown.

Specifically one can see in FIG. 3 the lower tool 40 of the punchingpress which is mounted on a lower frame plate of the punching press andwhich serves to receive the die 32 and also other parts and the upperframe plate 42 of the punching press on which an upper tool 44 and ahold down member 46 are mounted. Alternatively the plate 42 can be anintermediate plate of the punching press.

As shown the section 10 is supported in the press on all sides.

For this purpose the lower tool 40 has a receiving and support plate 48which receives the die 32 and supports two further plates 50 and 52which are arranged to the left and right of the section 10. The plates50 and 52 form a guide through which the bar section 10 can be moved onfurther in a direction perpendicular to the plane of the drawing stepfor step. The hold down member 46 which is pressed downwardly by meansof the illustrated springs which are braced against the upper tool 44 islocated in contact with the upper sides of the plates 50 and 52 and alsowith the upper side 30 of the section 10. The hold down member 46 has acylindrical opening in the form of a stepped bore 56 through which theplunger 28 extends and its end 56 can thus enter into contact againstthe upper side 30 of the section 10. At its upper end the plunger 28 isheld in the upper tool 44 and is pressed downwardly during the closingmovement of the press with the compensation pressure piece 58 of theupper frame plate 42 of the press until it has reached the position ofFIG. 3 and has thus formed the cylindrical projection 36. The shape ofthe cylindrical projection is determined by the shape of the die 32.This comprises an outer part 60 which is supported via a pressure piece62 at the lowest plate 41 of the tool 40 and is thus immovable relativeto the lower plate (not shown) of the press, since the plate 41 of thetool 40 is secured to the lower plate of the press.

The outer part 60 of the die has a projection 64 which fits in theU-shaped groove 22 in the lower side of the section 10 in the region ofthis station of the progressive tooling and has a central circular bore66 into which the material of the section can flow locally in order toform the ring-projection 36. The projection 64 has a heightcorresponding to the depth of the U-shaped groove 22 but does not fillout the undercuts 69, 71 at the inner inclined flanks 68, 70 of the twobars 14 and 16 of the section 10, since the section 10 has to be liftedat each step of the process and the undercuts must therefore remain freein the progressive tooling. The die 32 also has a centrally arrangedcylindrical post 72, the upper end of which in FIG. 3 supports a part ofthe lower side of the cylindrical projection 36. The end face of thepost 72 can be slightly curved and lie by a smaller amount above thecylinder 76 in order to assist the subsequent deformations of thesection 10. The post 72 is immovable and is supported at its lower endon a plate 62. The post 72 is also located within a cylinder 76 arrangedconcentric to it, the cylinder being supported at its lower end likewiseon the pressure piece 62 and having at its upper end a cylindricalring-surface which lies in a plane with the upper end face 74 of thepost 72 and with the latter forms the lower limit for the cylindricalprojection 36 formed by the action of the plunger 28.

Beneath the plate 62 and in a stepped bore 82 of the lowest plate 41 ofthe tool 40 there is located a moveable pressure piece 84 which isbiased upwardly by a spring 86 co-concentrically arranged in the steppedbore 82. Above the pressure piece 84 there are three cylindrical pins 88of which only two can be seen in FIG. 3, which are displaced angularlyby 120 degrees relative to another about the central longitudinal axis24 and extent through corresponding bores in the pressure piece 62 andcontact the lower end face 90 of the cylindrical part 76 of the die.

During the upsetting process the force of the plunger 28 (produced bythe punching press) is sufficient in order to press the cylindrical partof the die 67 downwardly through material flow in the section 10 intothe illustrated position, so that the pressure piece 84 likewise adoptsthe position shown in FIG. 3.

During the opening of the punching press, in order to carry out the nextstroke of the punching press, the upper tool 44 moves with the plunger28 and, offset phase-wise, the hold down member 46 moves upwardly awayfrom the plates 50, 52. The force of the spring 86 is then sufficient inorder to shift the cylindrical part 76 of the die upwardly via thepressure piece 84 and the pins 88 so that its upper ring-like end-face78 lies flush with the upper side of the projection 78 and the section10 is thereby lifted so that the cylindrical projection 36 is no longerarranged recess in the die, but rather located above the die, so that itcan be further transported into the next station of the progressivetooling (not shown). In addition the plates 50 and 52 are movedhorizontally apart from one another via a slider system mounted at theside in order to more easily lift the section 10. For example, sliderscan be fixedly attached to the right and left sides of the upper tool 44in FIG. 3 (only one slider shown) with the sliders being guided withtheir lower ends in respective guides 53 in the lower receiving plate 48and having inclined surfaces 55, 57 in the region of the plates 50, 52which cooperate with corresponding inclines surfaces 59, 61 at openingsof the plates in order to bring about the movement of the plates inaccordance with the double arrows shown in the plates for each stroke ofthe press. During this a new portion of the section 10 enters into theregion of the dies 32 so that through closing of the press a furthercylindrical projection 36 can be produced. The section of the section 10which was previously located in the upsetting station of the progressivetooling now has the cross-sectional shape of FIG. 2B, for which it is tobe said that the volume of the ring-like recess 34 corresponds to thevolume of the cylindrical projection 36.

In the next station of the progressive tooling (not shown) the sectionof FIG. 2B is now indented, i.e. provided with the ring-like recess 92of FIG. 2C. This ring-like recess or indentation 92 defines a breakawayedge 94, which is of advantage in order to achieve a clean punching edgefor the slug 96 while forming the punched aperture 98 in accordance withFIG. 2D in the next station of the progressive tooling.

In order to generate the indentation 92 of FIG. 2C the progressivetooling has in the second station in principal the same design as in thedrawing of FIG. 3 except that the central post 72 has a shape at itsupper end corresponding to the indentation 92 and projects by the axialdepth of the indentation above the upper end face 78 of the cylindricalpart 76 of the die. Under some circumstances it is possible to achievethe formation of the indentation simultaneously with the generation ofthe cylindrical projection 36. This is however not preferred, sinceduring the formation of the indentation one simultaneous re-corrects theshape of the cylindrical projection 36 so that it has a preciselydefined sharp shape in the region of the edge 100.

After the formation of the indentation 92 and the correction of theshape of the cylindrical projection 36 the section is once again liftedout of the die and transported by a further step to a station where thepunching of the aperture takes place in accordance with FIG. 2D. Thisstation is also in principal designed similar to FIG. 3, excepted herethe central post 72 is missing and the station has instead a bore whichforms a passage for disposal of the slug 96.

After the manufacture of the punched aperture in accordance with FIG. 2Dthe section is again lifted out of the corresponding die and transportedby a further step to a station where the dilation process is carried outso that the cylindrical projection 36 receives the shape which is shownin FIG. 2E. One notes that the lower end face of the cylindricalprojection 36 is provided with a conical recess 102 which forms achamfer, with the conical form diverging in the direction of the freeend face 104 of the cylindrical projection 36. In order to achieve thisshaping the corresponding station of the progressive tool is inprincipal also designed in accordance with FIG. 3, except that here thecentral post 72 is provided with a corresponding conical chamfer in theregion of its upper end.

In other respects, a free space (not shown) is provided in the region ofthe outer die 60 so that during the formation of the conical recess 102the outer sidewall 106 of the cylindrical projection 36 receives theconically downwardly diverging shape of FIG. 2E and hereby forms aring-like undercut 108 around the ring projection 36.

This undercut is, however, not essential. Indeed the dilation step,which forms the undercut 108, could be omitted, in particular wenn theconical recess 102 is formed during the indentation process. Thering-like piercing station would then have the right cylindrical form(outer shape) of FIG. 2D or FIG. 14C. An undercut in the region of thepiercing section, as shown at 108 in FIG. 2E is not necessary, since theundercuts 69 and 71 ensure the required press-out resistance. Anundercut such as 108, however acts to produce an even greater press-outresistance but makes the manufacture slightly more expensive through theadditional dilation step.

After the dilation process in accordance with FIG. 2E the section 10 isagain lifted out of the die, here also by a cylindrical part of the diesimilar to the part 76, and the section is transported by a further stepand indeed into a the region to a last station of the progressivetooling where a portion of the section is cut off having the length ofthe element 11 of FIG. 4. The so manufactured element with the punchedaperture 98 is now transported into an apparatus where the thread 110 isbored in a known manner in accordance with FIG. 2F. In some applicationsthe hollow body element is left without thread. For example the punchedaperture 98 could be intended as a guide or could be designed to receivean inserted part. Moreover, in motorcar construction, thread cutting orthread forming screws are frequently used, so that the thread 110 isfirst provided after the attachment of the hollow body element to asheet metal part, with a thread being provided using such a threadcutting or thread forming screw.

Various modifications are possible. On one hand the cutting to length ofthe individual elements from the section can take place before thedilation process of FIG. 2E, with the dilation process then also servingto correct the actual shape of the element in the sense that anydeformations during the cutting the length of the element are corrected.

Furthermore it is possible to carry out the upsetting process with aplunger which has a diameter in the region of its end carrying out theupsetting which is at least substantially the same as the diameter ofthe hole punch for the carrying out of the whole punching process. Thishas two advantages. On the one hand, the diameter of the ring-likerecess 34 is then of the same size as the diameter of the subsequentpunched aperture 98, so that the region of the recess 34 can form a partof the thread cylinder and the constructional height of the element canbe made correspondingly smaller. Since the cylindrical projection 36receives the shape of FIG. 2B and the volume of the cylindricalprojection 36 corresponds to the volume of the cylindrical recess 34 theaxial length of the cylindrical recess 34 becomes larger as a result ofthe smaller diameter of the plunger 28, so that the thickness of theregion of the section which has to be pierced during the apertureforming process in accordance with FIG. 2D is smaller and the apertureforming process is easier to carry out, so that the wear at the holepunch is less.

When the method is so carried out as shown in FIGS. 2A to 2E a nutelement 11 arises with the shape in accordance with the FIGS. 4A to 4F.The corresponding reference numerals from the previous figures areentered here and are thus to be understood in accordance with theprevious description.

FIG. 4B specifically shows the cross-section through the nut element 11of FIG. 4A at the section plane B—B whereas FIG. 4C shows thecross-section perpendicular thereto in accordance with the section planeC—C. The FIG. 4D shows the perspective illustration of the element 11from the right hand side and from the front in a view taken obliquelydownwardly, whereas the FIG. 4E shows a perspective representation ofthe nut element 11 from the lower side.

FIG. 4F recites the specific dimensions of the element when the threadis designed for an M6-screw. In the illustration of FIG. 4F the left andhalf of the cross-section drawing corresponds to the left hand side ofFIG. 4B, whereas the right hand half of the sectional drawing inaccordance with FIG. 4F corresponds to the half cross-section of theelement 11 in the direction of the longitudinal direction L of theoriginal section.

FIG. 5 now shows a component assembly comprising an element inaccordance with FIG. 4 after the attachment to a component 13 in theform of a sheet metal part. One notes that the sheet metal has beendeformed in the region of the lower side 12 of the element into therecess which is formed around the ring projection 36 within the U-shapedgroove 22 between the bars 14 and 16. In this arrangement the sheetmetal engages both in the undercuts 69 and 71 (only 71 shown in FIG. 5)and also in the undercut 108 around the cylindrical projection 36, sothat a form matched engagement takes place here and the element 11cannot any longer be removed from the sheet metal part 13 in the axialdirection 24 without the use of destructive forces. Through the formingof the sheet metal of the component 13 into the U-shaped groove 22between bars 14 and 16 the element 11 is prevented from rotatingrelative to the component 13, i.e. the element is able to withstand anyturning forces which can arise through the introduction of the screwinto the thread 110.

Since the aperture 112 in the component 13 is circular no notches arisehere which could lead, as a result of notch action to a prematurefailure of the component assembly by fatigue effects or cracks. A notchaction in the region of the ends of the bars is not to be expected sincethe ends are rounded off by the separation from the section strip and,as a result of the contact surface, do not produce any notches in thesheet metal part in the region of the bars. Situations are avoided inwhich the bars bury themselves into the component and hereby producenotch action. For this purpose the contact surfaces for the componentformed by the lower side of the bars are made so large that the surfacepressure lies below the yield point of the component. The aperture 112is produced during the attachment of the element by the ring-likeprojection 36 acting as a piercing section, for this purpose the die inaccordance with FIGS. 6A-6C is necessary.

As can be seen from FIG. 6B the die 114 has an essentially cylindrical,circularly round shape but is rather provided at one side with aflattened portion 116 which serves as a feature of shape which insures acorrect orientation of the die in the tool. It is namely necessary thatthe projection 118 at the end face 120 of the die, which is rectangularin outline, is aligned with the U-shaped groove 22 of the element 11.This correct alignment or orientation, i.e. about the axis 25 of thedie, which must be aligned with the axis 24 of the element during itsattachment, is insured by means of the flattened portion. The elementsmust also have the correct orientation around the axis 24 in the settinghead which is used for the attachment, which can be straight forwardlyinsured by the setting heads known per se.

For the attachment of the element 11 to the component 13 the component13 is normally positioned in a press, the element 11 is placed by asetting head and coming from above on the component 13 and the component13 is supported at the other side on the end face of the die. Duringclosing of the press the hold down member of the setting head firstmoves in a manner known per se against the upper side 122 of the sheetmetal part 13 and presses this into contact with the end face 120 of thedie. The setting head then moves the element 11 against the upper side120 of the sheet metal part, with the central axis 24 the element 11being coaxially positioned relative to the central axis 25 of the die.Since the ring projection 36 projects downwardly beyond the lower sideof the bars 14 and 16 the end face of the ring projection 36 is thefirst thing to contact the sheet metal part and cooperates with thecutting edge 122 of the projection of the die in order to cut a slug outof the sheet metal part 13, with this slug then being disposed ofthrough the central bore 124 of the die. The projection 118 of the diethen presses the sheet metal part into the U-shaped groove 22 and thering-like nose 126 of the die, which projects slightly above the plateauregion 128 in the four corners of the projection 118, presses the sheetmetal of the component 13, in the edge region of the punched aperture112 which has arisen through the punching out of the slug, into therecess around the ring protection 36 and simultaneously deforms thesheet material so that a ring-like recess 130 in the sheet metal partresults and the sheet material flows into the undercuts 69, 71 and, whenpresent, into the ring-like undercut 108. Instead of a press, a robot orother tool can be used to attach the element 11 to the component 13, therobot or other tool holding the element in the right position relativeto the die and applying the necessary force.

FIG. 7 now shows how a further component 132 can be screwed by means ofa screw 134 to the component 13. The further component 132 is namelyattached to the side of the component 13 which is remote from theelement 11, with the thread 136 of the screw 134 engaging into thethread 110 of the element 11. The contact surface 138 of the screw, orof a possibly provided washer (not shown) presses the further component132 against the component 13 so that the component 13 is trapped betweenthe bars 14 and 16 of the element and the further component 132. In thisconnection the axial height of the ring projection 36 in the axialdirection 24 is selected so that it does not hinder an intimate contactof the further component 132 on sheet metal part 13, i.e. thecylindrical projection 36 projects by the maximum amount of the sheetmetal thickness of the component 13 beyond the lower side of the bars 14and 16. With this design an extremely high security against rotation isachieved. Furthermore, the screw 34 pulls the element firmly against thesheet metal part 13 so that an axial separation of these two parts inthe axial direction 24 is not possible.

A further embodiment of the section of the invention and of the hollowbody element of the invention will now be described with reference tothe drawings of FIGS. 8 to 12.

For this description the same reference numerals are used as in thefirst embodiment of FIGS. 1 to 7, but increased by the basic number 200.Parts that are provided with the same reference numerals, i.e. aftersubtraction of the basic number 200, have the same function or the samedesign as the corresponding parts of the first embodiment in accordancewith FIGS. 1 to 7, so the description given there also applies for thecorresponding parts of this embodiment, unless something to the contraryis stated. It is principally the differences which will be described.

The section 210 of FIG. 8 also has a substantially rectangularcross-section here, with two grooves 223 and 225 being formed by a coldrolling process in the component side 212 of the section in contrast tothe embodiment of FIG. 1, the two grooves respectively havingtrapezoidal cross-sections with one inclined flank and extendingparallel to the longitudinal sides 218 and 220 respectively of thesection 210. Thus two bar-like regions 214 and 216 are also formed herewith respect inclined flanks 268 and 270 forming undercuts 269 and 271respectively.

The section 210 of FIG. 8 is processed in a punching press by means ofprogressive tooling similar to the previously described progressivetooling in order to produce the nut elements of FIGS. 9A to 9E.

During the manufacture of the nut element 211 in accordance with FIGS.9A to E the progressive tooling has a further station in comparison tothe previously described progressive tooling. In this additionalstation, which forms the first station when the section runs in, aconical recess 240 is first pressed in the lower side 12 of the section,in a type of inverse upsetting process, whereby a correspondingconically raised portion 242 arises at the upper side 230 of thesection, with both the conical recess 240 and also the conically raisedportion 242 being arranged concentric the axis 224 of the element. Afterformation of the conical recess 240 and the conically raised portion 242in the first station of the progressive tooling the cylindrical recess234 and the cylindrical projection 236 and subsequently the indentation292 and the punched aperture 291 are produced in further stations of theprogressive tooling in the same way and means as this was described inconnection with the FIGS. 2 and 3. The undercut 308 can also be omittedhere when a right cylindrical piercing section is desired. In the laststation of the progressive tooling the element 211 is then separatedfrom the bar section by a shearing process.

The precise end shape of the hollow body element can clearly be seenfrom the FIGS. 9A to 9E. The attachment of the element 211 to acomponent 213 takes place using a die 114 in accordance with the FIGS.12A and B which has several things in common with the die of FIGS. 6A to6C. First of all it should briefly be pointed out that the sectionaldrawing of FIG. 12A here shows two section planes which each show a halfsection corresponding to the arrows A—A in FIG. 12B.

Notable in the die 314 FIGS. 12A and B is, above all, that it has twobar like projections 246 and 248 which extend in parallel to another andare formed corresponding to the U-shaped grooves 223 and 225 in thelower side of the section, with the widths of the bars 248 being smallerby the double thickness of the component than the widths of thecorresponding grooves 223 and 225.

The ring projection 236 at the center of the end face of the die 314 iscircularly round in plan view here, with the manufacture of the ringprojection 326 leading to respective arched cut-outs 250 and 252 in thetwo bars 246 and 248 respectively. The axial height of the ringprojection in the die 314 is thus larger in this embodiment than in thedie of FIGS. 6A-C, since it projects directly out of the end face 320and not, as in the embodiment of FIGS. 6A-C, out of a rectangularprojection.

During the attachment of the element 211 to the component 213 utilizinga setting head, for example in a press, in a robot or in another type oftool, the bar like noses 246 and 248 of the die press the sheet materialinto the two U-shaped grooves 223 and 225 of the element 211 and intothe undercuts 269 and 271 and hereby form noses providing securityagainst rotation in the sheet metal part 213 which project into thecorresponding grooves 223 and 225. The marginal region 112 around thepunch hole in the sheet metal part is in this embodiment pressed intothe conical recess 240 around the cylindrical projection 236 and issimultaneously deformed into the undercut 308, with the flow of thesheet metal material into this undercut 308 as well as into theundercuts 269 and 271 being improved by the ring projection 326 of thedie, which leads to a ring-like recess 330 in the sheet metal partaround the cylindrical projection 236.

The attachment of a further component 332 takes place here in a mannersimilar to the embodiment of FIG. 7 using a screw 334. Here the furthercomponent 332 is also attached to the side of the component 313 remotefrom the element 311. It is particularly favourable in this embodimentthat the element 311 has a very large contact surface for the component313, since the grooves 223 and 225 and also the ring recess 240 onlytake up a smaller proportion of the lower side of the element 311area-wise than is the case in the previous embodiment. For this reasonthe element 311 can be made some smaller for the same contact surfacethan in the case of the element of the first embodiment, so that aweight saving is hereby achieved.

A third embodiment will now be described and indeed with reference tothe further drawings 13 to 17.

For this description the same reference numerals are used as in thefirst embodiment of FIGS. 1 to 7 but increased by the basic number 400.Parts which are provided with the same reference numerals, i.e. aftersubtraction of the basic number 400, have the same function and the samedesign as the corresponding parts of the first embodiment of the FIGS. 1to 7, so that the description given now also applies for thecorresponding parts of this embodiment unless something to the contraryis stated. It is principally the differences which will be described.

In the third embodiment of FIG. 13 the section 410 has a central region417 with a substantially rectangular cross-section and, to the left andright of this, integral wings 419 and 421 which extend at the componentside 412 beyond the central region 417 and there form two bars 414 and416 which extend parallel to the longitudinal sides 420 of the sectionand merge via an oblique recess 423, 425 respectively into the lowerside of the central region 417 of the section. In this arrangement theupper sides 427 and 429 of the two wings 419 and 421 respectively have aclear spacing from the upper side 430 of the central region 417 of thesection 410 and hereby form shoulders which stand oblique to thesidewalls of the central region and include an angle α with one anotherwhich, related to the sidewall 430 of the section remote from thecomponent side 412 is somewhat smaller than 180° and preferably lies inthe range from 175° to 160°.

The lower sides of the bars 414 and 416 are set obliquely in accordancewith the shoulders 427 and 429, i.e. form the same angle α to oneanother. The oblique transition regions 423 and 425 are likewiseparallel to the oblique surfaces formed by the shoulders 427 and 429 sothat they also form a corresponding angle α with one another. Thisoblique position of the wings 419 and 421 respectively relative to thecentral region 417 takes place during the manufacture of the section 410by cold rolling and has a special advantage, which will be explainedsomewhat later.

Apart from the special design of the wings 419 and 421 the shape of thesection 410 corresponds essentially to the embodiment of FIG. 1 and themanufacture of the nut elements from the section 410 takes place inprincipal in the same way and means as the manufacture of the nutelements in accordance with FIG. 4 as was previously described withreference to the FIGS. 2 and 3. The manufacturing process will thus notbe explained here in detail. One can see however from the FIGS. 14A to14E, which show the nut element in the finished form, and from thereference numerals used there, that this element has a large similarityto the element of FIGS. 4A to F.

One distinction here however lies in the fact that the cylindricalprojection 436 has no undercut, this is however not essential and thering projection 436 could have the same form as the correspondingprojection 36 of the embodiment of FIG. 4.

The attachment of the element 411 to the component 413, so that thecomponent assembly 415 arises, also takes place here using a die 514,and indeed the die of FIGS. 17A to C which is identical with the die 114of FIGS. 6A to C and must not be described more closely here, since thedescription for the embodiment of FIGS. 6A to C also applies here. InFIG. 17 the same reference numerals are used as in FIGS. 6A to C but aresimply increased by the basic number 400.

During the attachment of the element 411 for the formation of thecomponent assembly of FIG. 15 a setting head is however used in thisembodiment which permits the wings 419 and 421 to be, so to say pressedflat, so that the shoulders 427 and 429 respectively no longer form anangle α of less than 180° with one another but now lie in one plane. Inthis way the wings 419 and 421 respectively are, so to say, pivotedabout the pivot axis in the region of the inner ends of the inclinedsurfaces 423 and 425 respectively, so that the inner side edges 431 and433 of the bars 414 and 416 move towards from another and in theinstalled state have a smaller spacing from one another than before theattachment 411. That signifies that an undercut 435 and 437 respectively(FIG. 15) is now retrospectively formed in the region of the inner sidesurfaces 468 and 470 of the bars 414 and 416 respectively and that thesheet material now engages in form fitting manner into this undercut, sothat an axial separation of the element 411 from the component 413 indirection of the axis 424 is no longer possible. If the cylindricalprojection 436 of the element 411 is also formed with an undercut thepivotal movement of the wings 419 and 421 leads to the sheet material(also) being pressed into this undercut whereby an even more secureattachment of the element 411 to the component 413 takes place, i.e. theembodiment has a very high pull-out-resistance.

The situation during the attachment of a further component 532 is thenas shown in accordance with FIG. 16 and is in principal to be createdwith the assembly situation of FIG. 7, which is provided by the use ofthe same reference numerals (however increased by the basic number 400).

The functional elements described here can for example be manufacturedfrom all materials which achieve the strength class 5.6 or higher. Suchmetal materials are normally carbon steels with 0.15 to 0.55% carboncontent.

In all embodiments all materials can be named as an example for thematerial for functional elements which achieve, in the context of colddeformation, the strength values of class 8 in accordance with the ISOstandard, for example a 35B2-alloy in accordance with DIN 1654. Thefastener elements so formed are suitable for all commercially availablesteel materials for sheet metal parts which can be drawn as also foraluminium or its alloys. Aluminium alloys, particularly those of highstrength can also be used for the functional elements, for exampleAlMg5. Higher strength magnesium alloys such as for example AM50 canalso be considered for the functional elements.

1. An element for attachment to a component consisting of sheet metal,said element having a rectangular or square shape in plan view, with alower component engaging face and an upper face remote from said lowerface, first and second opposed longitudinal sides and third and forthopposed transverse sides extending between said first and second opposedlongitudinal sides, first and second bars provided at said lowercomponent engaging face and disposed at and aligned parallel to saidfirst and second longitudinal sides, a centrally arranged apertureextending perpendicular to said lower component engaging face, acylindrical component piercing projection present at said lowercomponent engaging face and disposed concentric to said aperture, and arecessed region present between said first and second bars and saidcylindrical component piercing projection, said first and second barseach having an inclined flank extending between said third and forthsides forming an undercut at a side facing said cylindrical componentpiercing projection.
 2. An element in accordance with claim 1, whereinfirst and second grooves are provided in said component engaging facespaced inwardly of and aligned parallel to said first and secondlongitudinal sides, thereby defining said first and second bars and saidrecessed region being present between said first and second grooves. 3.An element in accordance with claim 1, said first and second barsforming contact surfaces for said component which are sufficiently largethat a surface pressure at said surfaces arising in use lies below ayield limit of said component.
 4. An element in accordance with claim 3,said recessed region being a conical recess diverging in a directiongoing towards said component engaging face.
 5. An element in accordancewith claim 4, wherein a conical ring shoulder is provided at said upperface and has an approximately complementary shape to said conicalrecess.
 6. An element in accordance with claim 1, each of said inclinedflanks forming an angle α with a central axis of said cylindricalcomponent piercing projection in a plane perpendicular to a centrallongitudinal axis of said element and containing said centrallongitudinal axis, said angle α lying in the range between 3° and 45°.7. An element in accordance with claim 6, wherein said angle α lies inthe range between 7° and 30°.
 8. An element in accordance with claim 1,said cylindrical component piercing projection having a free end faceprojecting further from said component engaging face than said bars. 9.An element in accordance with claim 1, said recessed region between saidbars having a boundary and being at least substantially rectangular inoutline and said cylindrical component piercing projection beingarranged at a centre of said recessed region and having a spacing fromsaid boundary of the recess at all sides.
 10. An element in accordancewith claim 1, said cylindrical component piercing projection being atleast substantially circularly cylindrical.
 11. An element in accordancewith claim 1, said cylindrical component piercing projection having afree end face and an at least substantially conical outer wall whichdiverges going in a direction towards said free end face thereby forminga piercing edge with said free end face, said conically diverging outerwall forming an undercut.
 12. An element in accordance with claim 1,said cylindrical component piercing projection having a free end faceand a conical recess forming a chamfer in said free end face, saidconical recess diverging in the direction towards said free end face.13. An element for attachment to a component consisting of sheet metal,said element having a rectangular or square shape in plan view, with alower component engaging face and an upper face remote from said lowerface, first and second opposed longitudinal sides and third and forthopposed transverse sides extending between said first and second opposedlongitudinal sides, first and second grooves provided at said lowercomponent engaging face spaced inwardly of and aligned parallel to saidfirst and second longitudinal sides whereby first and second bars areformed at and extending parallel to said first and second longitudinalsides, a centrally arranged aperture extending perpendicular to saidlower component engaging face, a cylindrical component piercingprojection present at said lower component engaging face and disposedconcentric to said aperture, and a recessed region present between saidfirst and second grooves and surrounding said cylindrical componentpiercing projection, said first and second bars each having an inclinedflank extending between said third and forth sides forming one side ofthe respectively associated first and second grooves.
 14. Componentassembly comprising a component and an element attached thereto, saidelement having a rectangular or square shape in plan view, with a lowercomponent engaging face and an upper face remote from said lower face,first and second opposed longitudinal sides and third and forth opposedtransverse sides extending between said first and second opposedlongitudinal sides, first and second bars provided at said lowercomponent engaging face and disposed at and aligned parallel to saidfirst and second longitudinal sides, a centrally arranged apertureextending perpendicular to said lower component engaging face, acylindrical component piercing projection present at said lowercomponent engaging face and disposed concentric to said aperture, and arecessed region present between said first and second bars and saidcylindrical component piercing projection, said first and second barseach having an inclined flank extending between said third and forthsides forming an undercut at a side facing said cylindrical componentpiercing projection, said component being formed into said undercutsformed by said inclined flanks of said first and second bars and intosaid recessed region adjacent to the said bars and to said cylindricalcomponent piercing projection, said element being hereby latched to saidcomponent in a manner secure against press-out and relative rotation.15. Component assembly in accordance with claim 14, said component beingmoulded into an undercut formed by said cylindrical component piercingprojection.
 16. Component assembly in accordance with claim 14, saidcomponent having a ring-like recess in said recessed region around saidcylindrical component piercing projection.